Electronic tube device



'Jan. 17 1967 R. A. FREGGENS 3,299,310

ELECTRONIC TUBE DEVICE Filed ma 28, 1964 I 3 Sheets-Sheet 1 Fig.l.

INVENTOR WITNESSES I i Robert A. Freggens KTTORNEY 'Jan, 17, .1961 I R. A. FREGGENS 3,299,310

v ELECTRONIC TUBE DEVIGE Filed May 28, 1964 3 Sheets-$heet 2 I FREGGE-NS v 3,299,310

I ELECTRONIC TUBE DE ICE ril ajmay as, 964 :3 w e MOMENTI 9| 62 62 9 86 CATHODE PERI METER PERIMETER 89 United States Patent 3,299,310 ELECTRONIC TUBE DEVICE Robert A. Freggens, I-Iorseheads, N.Y., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a

corporation of Pennsylvania Filed May 28, 1964, Ser. No. 371,011 19 Claims. (Cl. 313--278) sembly operate at substantially elevated temperatures in the range of 1700 C. to above 2000 C. At these higher temperatures, there is a tendency for the filament elements to expand and contract in response to variations in temperature. In most power tube constructions a cylindrical grid concentrically surrounds this cathode assembly. It has been found that a very close and constant spacing must be maintained at all times between the individual filament elements and the concentric grid for the tube to have a uniform operation. However as the filament elements cool from these elevated temperatures, the filament elements tend to contract and the structure supporting the strands is bent and the alignment of the filament elements will become ask'ewed. As a result, the spacing between the filament elements and the grid may vary and therefore the operational characteristics of the tube will differ over the temperature range to which the filament elements are subjected.

It has been recognized that the operation of an electronic device as that described above may be kept uniform by maintaining constant tension on each filament element as the temperature varies inside the tube. By so regulating the tension, the filament elements will remain aligned with respect to each other and with respect to the concentric grid with the result that the operational characteristics of the tube will remain uniform.

One solution for this problem has been proposed by the Patent No. 2,632,129 to Dailey et al. wherein the tension is applied to the individual filament elements through a universally pivoted support member. A universally mounted support member is carried upon a standard and the individual filament elements are mounted on yoke elements which are held in restraining slots on the support member. Itis noted that the cathode support suggested by Dailey appears to be limited to those applications where a relatively few number of filament elements are to be mounted.

The invention is particularly adapted for use in very high power vacuum tubes, wherein the current passing through the cathode may exceed 400 amperes. In order to handle this amperage it has been found necessary to use a great number of cathode filament elements. As many as forty-eight separate elements or more have been used to accommodate the amperes passing through the cathode. It can be seen that if a great number of elements such as 48 elements were to be mounted on a support as disclosed by Dailey, that the support would be so secured to the base of the electron tube device so that the universally mounted support member could not pivot so as to relieve the various tensions of the filament elements.

As explained above, it is necessary to use a great num- I patent, the filament elements are suspended from yoke elements or saddle supports. To align each of the filament elements into the cylindrical array, it is necessary to position the saddle supports so that each support lies on a tangent to a circle concentric with the grid. When only a few filament elements are to be suspended, as in the Dailey patent, the suspension of the filament elements is relatively simple. However, when it is necessary to suspend a large number of filament elements, a moment torque will be placed on each of the saddle supports and, therefore, on the remaining portion of the suspension system due to the fact that the saddle supports must be placed in a tangential relationship to a circle concentric with the grid.

In one particular embodiment of applicants invention, a three phased voltage is applied across the cathode assembly. In order to provide insulation between these phases, the support members for suspending the filament elements are mounted on a fulcrum mount made of a ceramic material. Since ceramics are strong in compression but not in tension, it is important to avoid placing torque forces or other non-compressive forces upon the fulcrum mount supporting the support members. The repeated application of such forces due to the many changes in tube temperature may cause the ceramic to crack and the support members to break away.

Accordingly, it is' the general object of this invention to provide a new and improved cathode assembly mounting structure.

It is a more particular object of'this invention to provide a new and improved cathode assembly mounting structure capable of mounting a great number of filament elements.

Another object is to provide an improved high power vacuum tube having a cathode assembly comprising a great number of filament elements.

A further object is to provide a lever suspension system for the cathode filament elements wherein the torque moments produced by the filament elements are equalized.

A still further object of this invention is to provide a support for the filament elements which is capable of maintaining the tension applied to the filament elements of a cathode assembly and to maintain such tension on a great number of filament elements.

Another object of this invention is to place compressive forces on the fulcrum mount and the lever suspension system rather than torque forces.

Briefly, the present invention accomplishes the above cited objects by suspending a great number of filament elements from a lever system in which the levers of this system are so interconnected that an opposite and equal torque is produced to cancel the torque created by the filament elements. More specifically, the levers are inter connected so that the forces pulling downwardly on one lever are transmitted to the next lever at a point offset from the center or reaction line of that lever. By displacing the point at which the downward forces react, a moment arm is established about the lever thereby producing a moment torque which is designed to equalize the torque created by the filament elements. In one specific embodiment of this invention, such a moment arm is established by interconnecting one lever to a bent or angled portion of the next lever. Another feature of this invention provides that the levers may be interconnected by a link member to recess a lever so that it will not contact the grid.

A still further feature of this invention provides an upwardly biased platform to provide a level, peripheral support for the lever systems.

Further objects and advantages of this invention will become apparent as the following description proceeds and features of novelty which characterize the invention 3 will be pointed out in particularity in the claims annexed to and forming a part of this specification.

For a better understanding of the invention, reference may be had to the accompanying drawings in which:

FIGURE 1 shows a sectional view of an electronic tube device in which the cathode assembly of this invention has been placed;

FIG. 2 shows a view of the filament elements and their suspension system which comprise an embodiment of this invention;

FIG. 3 shows a partial sectional view of a fulcrum mount and a lever mounted thereon;

FIG. 4a shows a partial plan view of the support system which comprises an embodiment of this invention;

FIG. 4b shows a plan view of the first lever of the support system shown in FIGURE- 4a;

FIG. 5 shows a partial side view of the lever linkage system shown in FIGURE 4a; and

FIGURES 6 and 7 show partial views of the individual levers of the support system shown in FIGURE 4a.

Referring to FIG. 1, an electron tube, such as the WX- 4852 of the assignee, is shown employing a novel cathode assembly 10. Filament elements or electrodes 16 are arranged in a circular array and suspended from a support system 60. The cathode assembly is mounted concentrically within an evacuated envelope comprising a cylindrical anode or plate element 17, a cylindrical glass insulator 32 and a grid deck 29. The plate element 17 is made of an appropriate conductive material such as copper and has an annular lid 17:: extending from the open end thereof. A cylindrical bracket ring 19a is attached as by brazing to the plate element 17. The glass insulator 32 has another bracket ring 19b made of a material such as alloy of cobalt, nickel and iron usually sold under the trademark of Kovar sealed to one end thereof and another such bracket ring 21a sealed to the other end of the glass insulator 32. The glass insulator 32 may be made of a glass material such as a boron silicate marketed under the Corning designation No. 7052 or a high-purity alumina ceramic. The rings 19a and 1% may be hermetically attached as by a heliarc welding process. One end of another bracket ring 21b similar to that described above is secured to the grid deck 29 and the other end is heliarc welded to ring 21a. The envelope just described may be evacuated through exhaust tube 23 which may be cold-welded to seal the envelope.

A water jacket 14 with appropriate inlet and outlet conduits 14a and 14b may be concentrically fit over the plate element 17 and secured as by bolting to the lid 17::

of the plate element 17. With high power electron tubes of the nature herein described, it is often necessary to dissipate the heat generated within the tube by the use of a coolant flowing through jacket 14.

A cylindrical grid electrode or control element 12 is positioned concentrically of the circular array of filament elements 16. As will be emphasized later in detail, the spacing between the filament elements 16 and the grid electrode 12 is a critical dimension and has to be maintained constant to ensure uniform operation of the electron tube. In one embodiment, this spacing has been set at .180 inch. The grid electrode 12 is positioned in place by a grid support cone 34 set upon the grid deck 29.

The filament elements 16 are secured at their base to filament supports 18. As will be explained in greater detail later, the filament supports 18 are mechanically and electrically connected to a terminal plate 20. There are three terminal plates each accepting one of the three phases of voltages applied to the filament elements 16. Each terminal plate 20 as can be seen more clearly in FIG. 2 forms a 120 slice of the circular array of these plates. There is secured to each of the terminal plates 20 a current conductor 26 (see FIGURE 1) which extends from one of the terminal plates 20 to a phase terminal 28. The phase terminals 28 are mounted in a circular array upon the grid deck 29. The phase terminals 28 are made of a suitable conductive material such as copper and are insulated from the grid deck 29 by a cylindrical ceramic insulator 27 which is secured to the grid deck 29 by a flange made of an alloy of cobalt, iron and nickel similar to those described above.

Referring now to FIG. 2, there is shown in detail the cathode assembly 10. At the center of the assembly 10 there stands a support rod or standard 40. Mounted upon the standard 40 is a cylindrically shaped mounting assembly 55 consisting of an upper platform or member 42 and a lower platform 43 spaced from each other by support columns 45. As can be seen in FIG. 2 shaft mounts 52 are secured to both the upper platform 42 and the lower platform 43. In order to facilitate the movement of the mounting assembly 55 upon standard 41), ball bearings 53 are positioned within the mounts 52. The ball bearings 53 may be fashioned from sapphire.

A plurality of support pads 44 may be welded or riveted on the upper platform 42 so as to extend beyond the periphery of the upper platform 42. Ordinarily the support pads 44 are of a triangular configuration with the broad part of the triangle positioned on the upper platform 42 to give maximum support. Upon the apex portion of the triangle, a fulcrum mount 46 is positioned. Three groups of filament elements 16, each group repre senting avoltage phase, are mounted on the upper platform 42. In order to insulate one phase from the other, the fulcrum mounts 46 are made of insulating material such as a ceramic material. In particular, alumina has been found to be particularly adapted for these mounts. As shown in FIG. 3, the fulcrum mount 46 has a slot in which there is placed a first lever bar 71). A notch 106, which is centrally disposed of the length of first lever bar 70, rests upon a ball bearing 102. The ball bearing 102 is made of a suitable material such as molybdenum and is positioned in a depression 104 of the slot 100.

Referring now to FIG. 2, a plurality of filament elements 16, representing one of the three voltage phases, is shown suspended from the mounting assembly 55. From each fulcrum mount 46 there is balanced one of the lever systems 66 which will be described in detail later. Each filament element 16 is shaped so as to form an elongated U. The bight of the U is suspended by a saddle support 62 which is in turn connected to the support system 61). One end of the looped filament element 16 is connected to filament support 18a, and the other end is connected to filament support 18b. Filament sup ports 18a extend through'an aperture 51 in a support deck 50 and is electrically and mechanically connected to the terminal plate 20. The other filament support 18b is secured directly to the support deck 50. Apertures 51 are made of such diameter as to prevent electrical contact between filament support 18a and the support deck 50. The support deck 50 is secured to each of the terminal plates 20 by screws (not shown). The terminal plates are insulated from the support deck 51) and from each other by insulating washers (not shown) which are inserted between the screws and the support deck 50.

In one embodiment of this invention, the cathode assembly 10 comprising three groups of filament elements 16 is connected to a Y configuration to neutral. As can be seen in FIGURES 1 and 2, the line voltages are applied through conductors 26 to the terminal plates 20 which are in turn connected to the filament supports 18a One end of the filament elements 16 are connected to the cathode supports 18a while the other end of filament elements 16 are connected through the cathode supports 18b to the support deck 50 which forms the neutral point for each group of filament elements. Therefore, it can be seen that each group of filament elements 16 forms one leg of the Y configuration with neutral point being placed at the support deck 50.

In order to apply an upward force to the filament elements 16, three compression springs 54 are placed in a circular array concentric with the mount 52 in the lower platform 43. The compression springs 54 rest on the support deck 50 and exert an upward force against the support assembly 55 thereby placing the filament elements 16 under tension. As stated above the mounting assembly 55 has mounts 52 on the upper and lower platforms 42 and 43 thereof through which there extends standard 40. Thus, the mounting assembly 55 is slidably mounted on the standard 40 in a linear direction and may readjust due to the force of the compression springs 54 to compensate for the differing lengths of the filament elements 16.

Though it is noted that the various elements described above could be made of many elements which would occur to one skilled in the art, specific examples of the materials used in one particular embodiment will be given. The filament elements 16 could be made of either thoriated or pure tungsten. The upper and lower platforms 42 and 43, the support columns .45, and the standard 40 could be made of an inexpensive metal such as molybdenum. .The support deck 50 and the terminal plates 20 could be made of copper or Monel or molybdenurn. Finally, the compression springs 54 could be made of tungsten or a tantalum tungsten.

Now referring to FIGS 2 and 40, there is shown the support system 60 which suspends the filament elements 16. The purpose and function of the support system 60 is to first equalize the axial or vertical forces acting upon the filament elements due to the different rate of expansion of each element as the tube temperature is varied, and secondly to equalize. the torque moments produced by the pivotally mounted saddle supports 62. The support system 60 comprises the first lever bar 70 which is pivot-ally mounted upon the fulcrum mountv 46 at the center of the first lever bar 70. The ends of the first lever bar 70 are bent so as to form angle portions 72 upon which are mounted a second lever bar 74. The second lever bars 74 are pivotally mounted by a fastening rivet 76 extending through the center of the second lever bar 74 and the angle portion 72. As shown in FIG. 4b a reaction line (shown by a dotted line) passes through the first lever bar 70. It is noted that the reaction line of the first lever bar 70 passes through the pivoting point of the second lever bar 74, i.e., the fastening rivet 76. Both ends of the second lever bar 74 are likewise bent forming angle portions 78. As can be more clearly seen in FIG. 2, a link 80 is pivotally connected by a fastening rivet 81 on the angle portion 78 of the second lever bar 74. To the lower portion of the link 80 a third lever bar 85 is pivotally mounted by a fastening rivet 86. Both ends of the third lever bar 85 are likewise bent forming angle portions 89 upon which are pivotally mounted the saddle supports 62 for the filament elements 16. In summary, each lever bar of the support system 60 is connected pivotally to the next lever bar to form a series of levers suspending the filament elements 16 from the platform 42.

As stated above in the objects, one aim of this invention is to equalize the torque moments operating on and through the support system 60. In order to eliminate these torque moments, the angle portions of the various lever bars have been bent to certain angles so that resulting moments created by the filament elements 16v are equalized and cancelled.

Referring now to FIGS. 4a and 4b, it may be seen that the first lever bar 70 has a reaction line passing along the length thereof (the reaction line is shown in FIG. 4b as a dotted line). angle portion 72 by the fastening rivet 76. It can be seen that the forces acting downwardly on the second lever bar 74 will concentrate at its point of pivoting, i.e. the fastening rivet 76. As shown in FIG. 4b, the angle portion 72 has been bent to such an angle and the fastening rivet 76 The second lever bar 74 is connected to the has been so placed on the angle portion 72 that the reaction line passing along the length of the first lever bar 70 coincides precisely with the point of pivoting; therefore, since the downward forces are acting through the point of pivoting which coincides with the reaction line, there is no moment arm about which the downward forces may act. As a result, since there is no moment arm, there will likewise be no moments produced about the first lever bar 70.

As mentioned above, a great number of filament elements 16 are necessary to carry the great amounts of amperage through the cathode assembly 10. In addition, it is necessary to mount each of the filament elements 16 equally spaced from the cylindrical grid 12. In order to achieve the equal spacing of each filament element 16, the saddle supports 62 suspending the filament elements 16 have been placed tangent to the perimeter of a circle which is concentric to the cylindrical grid 12. Such a circle is shown in FIGS. 4a and 6 and is therein designated as the cathode perimeter. As more particularly shown in FIG. 6, the saddle support 62 which suspends the filament element 16 is positioned to be tangent to the cathode perimeter. However, when the saddle supports 62 have been place-d to be tangent with the cathode perimeter, the forces created by the filament elements 16 acting downwardly on the angle portions 89 of the third lever bar 85 will cause a counterclockwise torque on the third lever bar 85 (see FIGS. 5 and 6). To achieve the desired placement of the filament elements 16 and the saddle supports 62, the angle portions 89 are necessarily bent at a slight angle with respect to the reaction line running along the length of the third lever bar 85. When the angle portions 89 are bent at a very slight angle, the forces acting downwardly on the saddle support 62 will concentrate at a pivoting point which is offset from the reaction line of the third lever bar 85 by a distance designated as moment arm A (see FIG. 6). Therefore, a moment torque will be created about the third lever bar 85 in a counterclockwise direction (as shown by the arrow in FIG. 5)

In order to equalize the counterclockwise torque created about the third lever bar 85, a moment torque of opposite and equal value has to be created within the support system 60. In one particular embodiment of this invention, this counterclockwise moment has been cancelled by producing an opposite and equal moment torque in the second lever bar 74. Referring now specifically to FIG. 7, the link through which the downward forces act on the second lever bar 74 has been pivotally connected by the fastening rivet 81 so that the downward forces will concentrate at a point of pivoting that is offset from the reaction line (as shown by a dotted line in FIG. 7) of lever bar 74. The distance that the pivoting point is offset from the reaction line has been designated as moment arm B. It may be seen by a comparison of FIGURES 6 and 7 that moment arm B has been placed on the opposite side of the reaction line of the second lever bar as compared with the placement of the moment arm A with respect to the reaction line of the third lever bar 85. As a result, the forces acting down through the pivoting point of the second lever bar 74 will create a clockwise torque about the second lever bar 74, which by design is of opposite and equal value to the counterclockwise torque created about the third lever bar 85.

Referring now to FIG. 5, it can be seen that if the counter clockwise torque created through the fastening rivet 91 is balanced by an opposite and equal torque such as that created through the fastening rivet 81 of the second lever bar 74 that the unwanted torque created on the third lever bar will be cancelled or equalized with the result that no torque will be placed upon the secondlever bar 7 4.

The link 80 is inserted between the angle portion 78 of the sec-ond lever bar .7 4, and the third lever bar 85. As can be seen in FIG. 5, the link 80 allows the third lever bar 85 to be positioned directlybeneath the angle portion 78 and also to freely rotate with respect to the second lever 7 bar 74. Further it .can be seen that if the third lever bar 85 had been connected directly to the second lever bar 74, the second lever bar '74 would have projected out into the region between the filament elements 16 and the grid 12 due to the short length of the third lever bar 85.

Therefore, the insertion of link 80 allows the second lever bar 74 to be recessed slightly from the cathode perimeter and also allows the third lever bar '85 to be freely pivotally mounted.

As shown in FIGS. 4b, 6 and 7, the moments about a reaction line of each lever bar may be adjusted in several different manners. The angle portion of each lever bar may be bent at various angles in order to offset the pivoting point through which the downwardly acting forces may concentrate, or the fastening rivet connecting the next member below to that angle portion may be offset varying distances from the point of the bend of the angle portion. Further, it may be appreciated that the same effect could be achieved by varying the thickness of the various members so connected; that is to say that the thickness of the varying lever bars could be varied so as to reposition the point of pivoting. Further, the thickness of the link 86 and the lever bars to which it is connected could be varied in order to appropriately position the point of pivoting with respect to the reaction line of these lever bars.

Referring now to FIGS. 1 and 2, it can be seen that the cathode filament elements 16 are mounted in three groups on the support systems 60. As explained above, there are three support pads 44 upon which may be mounted the support systems 60. Each group of lever bars are isolated electrically from each other by the ceramic fulcrum mount 46, thus allowing a three phase excitation of the filament elements. Three phase excitation of the cathode assembly 10 is advantageous in that it reduces A.C. hum and consequent space change modulation of the tube currents. This allows low hum in broadcast service and low ripple when used as a switch tube in rectangular pulse modulators. Further, the interconnections may be modified by proper paralleling of the cathode terminals and support decks so as to provide for single phase excitation of the filament elements.

It will, therefore, be apparent that there has been disclosed a support structure for a plurality of cathode filament elements which will place a vertical thrust on each of the filament elements and also a structure which will equalize the torque moments created by the downward forces of the contracting filament elements.

While it has been shOWn and described what are at present considered to be the preferred embodiments of the invention, modifications thereto will occur to those skilled in the art. It is not desire-d, therefore, that the invention be limited to the specific arrangements shown and described and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

I claim as my invention:

1. An electrode assembly for suspending a large number of filament elements comprising a standard, a mounting assembly being flexibly biased upward along said standard, means for maintaining the angular position of said mounting assembly fixed with respect to said filament elements, means for suspending one end of said filament elements from said mounting assembly, said means for suspending being freely pivoted about a single point of said mounting assembly and means for rigidly securing the other end of said filament elements so that said filament elements are maintained under substantially equal tension.

2. An electron device including an electrode, and a cathode assembly comprising a plurality of filament elements, a mounting assembly, and a support system for suspending said plurality of filament elements from said mounting assembly, said support system including at least first and second lever bars, said filament elements being connected to said first lever bar so as to establish a first moment torque upon said first lever bar, said second lever bar having at least one offset portion, said first lever bar being interconnected to said offset portion of said second lever bar so as to produce a sec-0nd torque moment of a magnitude equal and opposite to said first torque moment.

3. An electron device comprising an electrode and a cathode assembly comprising a plurality of filament elements, a mounting assembly, a support system for suspending said plurality of filament elements from said mounting assembly, and means for securing each filament element from said support system, said support system including at least first and second lever bars, each filament element being connected to said first lever by said means so as to produce a first torque moment on said first lever bar, said first lever bar being interconnected to said second lever bar so as to produce a second torque moment'of a magnitude equal and opposite to said first moment torque to thereby equalize said first moment torque.

4. An electron device comprising an electrode, and a cathode assembly comprising a plurality of filament elements, a mounting assembly, a support system for suspending said plurality of filament elements from said mounting assembly, and means for securing each filament element from said support system, said support system including at least first and second lever bars, each of said lever bars having a reaction line, said means for securing each filament element being connected to said first lever bar at a point offset from the reaction line of said first lever bar to produce a first moment torque about said first lever bar, said first lever bar being so connected to said second lever bar to produce a force acting at a point offset from the reaction line of said second lever bar to produce a second moment torque of an opposite sense to said first moment torque.

5. A filament element support for an electron discharge device having an upwardly biased mounting assembly and a support system, said support system comprising a first lever bar pivotally mounted on said mounting assembly, a second lever bar pivotally mounted on both ends of said first lever bar, a link member pivotally secured at one end to each end of said second lever bar, a third lever bar pivotally mounted to the other end of said link member, and means for suspending said filament elements so connected to each end of said third lever bar to produce a first moment torque about said third lever bar, said link member being secured to said second lever bar to produce a second moment torque of a magnitude opposite and equal to said first moment torque.

6. An electron device comprising an electrode having a first surface of. predefined configuration, and a cathode assembly comprising a plurality of filament elements, a support system for suspending said plurality of filament elements, and means for securing each filament element from said support system, said support system including at least first and second lever bars, each of said lever bars having a reaction line, said means for securing being aligned tangentially to a second surface all of whose points are equal distant from said first surface and being connected to said first lever bar at a point offset from the reaction line of said first lever bar to produce a first torque moment, said first lever bar being operatively connected to said second lever bar to produce a force acting at a point offset from the reaction line of said second lever bar to produce a second moment torque of a magnitude of an -opposite sense to said first moment torque.

7. An electron device comprising an electrode, and a cathode assembly comprising a plurality of filament elements, a support system for suspending said plurality of filament elements, and means for securing each filament element from said support system, said support system including at least first and second lever bars, each of said lever bars having a reaction line and end portions bent y 9 at an angle with respect to said reaction line, said mean for. securing connected to the end portions of said first lever at a point offset from the reaction line of said first lever bar to produce a first torque moment about said first lever bar, said first lever bar being operatively connected with the end portions of the second lever bar at a'point offset from the reaction line of said second lever bar to produce a second moment torque of an opposite sense to said first moment torque.

' 8. An electron device comprising a cylindrical electrode, a plurality of filament elements arranged in circular fashion concentrically with respect to said cylindrical electrode, a platform member flexibly biased to apply a tension on said plurality of filament elements, means for suspending said plurality of filament elements from said platform including at least one lever bar, said lever bar being pivotally suspended to apply said tension substantially equally to said filament elements, and means for maintaining said platform at substantially the same angle with respect to said filament elements to thereby insure a constanti'spacing between said filament elements and said cylindrical electrode.

9. An electron device comprising a cylindrical electrode, a plurality of filament elements arranged in a circular array concentrically with respect to said cylindrical electrode, a standard, a platform supported on said standard and upwardly flexibly biased to provide horizontal support at the periphery of said platform, and means for mounting said plurality of. filament elements on the periphery of said platform, said means for mounting including at least first and second lever bars, said lever bars having a reaction line, said first lever being connected to said second lever bar at a point offset from the reaction line of said second lever bar to produce a compensating torque moment.

10. An electron device comprising a cylindrical electrode, a plurality of filament elements arranged in a circular array concentrically disposed with respect to said cylindrical electrode, a standard, a mounting assembly comprising upper and lower platform members, said platform members being spaced from each other and held in a fixed angular relation with respect to said filament elements, apertures in said platform members, said mounting assembly being mounted on said standard with the standard protruding through said apertures, means for biasing said mounting assembly along said standard, and means for suspending said plurality of filament elements from said upper platform member, said means for suspending including at least one lever bar for establishing substantially equal forces upon said filament elements connected thereto. I

11. An electron discharge device including an electrode and a cathode assembly including a plurality of filament elements, a. mounting assembly, and means for suspending said plurality of filament elements from said mounting assembly, said plurality of filament elements connected to said means for suspending so as to produce a first moment torque upon said means for suspending, said means for suspending including means for providing a sec-nd torque moment of a magnitude and sense to equalize said first moment torque.

12. An electron device comprising a plurality of filament elements; a mounting member; and means for suspending said filament elements from said mounting member including at least one lever bar for providing substantially equal forces upon said filament elements connected to said lever bar, said filament elements being connected to said lever bar to place a first moment torque on said lever bar, and means for connecting said lever bar to said mounting member and for providing a second moment torque in an opposite sense to said first moment torque.

13. An evacuated electron device including a cylindrical electrode, and a cathode assembly including a plurality of filament elements, a mounting assembly, and a means for suspending said plurality of filament elements from said mounting assembly in a circular array concentrically disposed with respect to said cylindrical electrode, said means for suspending including at least one lever bar, said lever bar having portions disposed parallel to a plane tangent to said cylindrical electrode, said filament elements being connected to said portions of said lever bar to produce a first moment torque about said lever bar, said means for suspending providing a second moment torque of substantially equal and opposite magnitude so as to cancel said first moment torque.

14. An evacuated electron device including a cylindrical electrode, and a cathode assembly including a large numberof filament elements, a mounting assembly and a means for suspending said filament elementsfrom said mounting assembly in a circular array concentric with said cylindrical electrode so that each of said filament elements is equally spaced from'said control element, said means for suspending including at leastfirst and second lever bars said first lever bar having portions disposed parallel to a plane tangent to said cylindrical electrode, said filament elements being connected to said portions of said first lever bar to provide a first moment torque about said first lever bar, said first lever bar being interconnected with said second lever bar to provide a second torque moment of substantially equal and opposite magnitude to said first moment torque to thereby equalize said first moment torque.

15. An electron device including an electrode of defined configuration; and a cathode assembly comprising a plurality of filament elements, a mounting member, and a system for suspending said plurality of filament elements from said mounting member including at least one lever bar for providing substantially equal forces on said filament elements connected thereto, said first lever bar having a reaction line along the length thereof and portions disposed parallel to a plane tangent to said configuration of said electrode, said filament elements connected to said portions at a point off-set from said reaction line to establish a first moment torque on said first lever bar, and means disposed between said first lever bar and said mounting member for providing a second moment torque of a magnitude and sense to equalize said first moment torque.

16. An electron device as claimed in claim 15, wherein said means includes a second lever bar having a reaction line along the length thereof, said first lever bar interconnected to said second lever bar at a point olfset from said reaction line of said second lever bar to establish a second moment torque of a magnitude equal and opposite to said first moment torque.

17. An electron device including an electrode of defined configuration; and a cathode assembly comprising a plurality of filamentelements, a mounting member, and a system for suspending said plurality of said filament elements from said mounting member including first, second and third lever bars for establishing substantially equal forces upon said filament elements, said first, second and third lever bars having reaction lines along the length thereof and portions disposed at angles with respect to said reaction lines, said portions of said first lever bar disposed parallel to a plane tangent to said configuration of said electrode, said filament elements connected to said portions at a point offset from said reaction line to establish a first moment torque on said first lever bar, and a link member for pivotally mounting said first lever bar and interconnected to the portions of said second lever bar at a point off-set from said reaction line of said second lever bar to establish a second moment torque of a magnitude equal and opposite to said first moment torque, said second lever bars being pivotally connected to said portions of said third lever bars at a point coincident with said reaction line of said third lever bar.

1 l 18. An electron device comprising a cylindrical electrode, and a plurality of filament elements arranged in a circular array concentric With respect to said cylindrical electrode, a mounting member flexibly biased in a direction parallel to that of said filament elements, means for 5 maintaining the angular orientation of said mounting member with respect to said filament elements, a system for suspending said filament elements from said mounting member and including at least one lever bar for establishing substantially equal forces upon said filament 10 elements connected thereto, said lever bar having portions disposed parallel to a plane tangent to said cylindrical electrode, said filament elements connected to said portions to provide a first moment torque on said lever bar, and means disposed between said lever bar and said mounting member for providing a second moment torque of a magnitude and sense to equalize said first moment torque.

19. An electron device comprising a cylindrical electrode, and a cathode assembly including a plurality of filament elements, a system for suspending said plurality of filament elements, and a mounting member providing a surface for supporting said system for suspending, means for maintaining said surface at a fixed angular orientation with respect to said plurality of filaments, terminal means, said filament elements being formed into the shape of a loop With the end portions secured to said terminal means, said system for suspending including at least one lever bar having end portions disposed parallel to a plane tangent to said cylindrical electrode, said loop having a bite portion Which is secured to said end portions of said lever bar so as to place a first moment torque upon said lever bar, means for biasing said mounting member so as to apply substantially equal tension upon said filament elements, and means disposed betvveen said lever bar and said mounting member for establishing a second moment torque of such magnitude and sense to equalize said first moment torque.

References Cited by the Examiner UNITED STATES PATENTS 2,632,129 3/1953 Dailey 313272 3,218,502 11/1965 Freggens 3l3'278 X I FOREIGN PATENTS 643,092 9/1950 Great Britain.

846,587 8/1952 Germany.

JOHN W. HUCKERT, Primary Examiner.

25 A. 1. JAMES, Assistant Examiner. 

1. AN ELECTRODE ASSEMBLY FOR SUSPENNDING A LARGE NUMBER OF FILAMENT ELEMENTS COMPRISING A STANDARD, A MOUNTING ASSEMBLY BEING FLEXIBLY BIASED UPWARD ALONG SAID STANDARD, MEANS FOR MAINTAINING THE ANGULAR POSITION OF SAID MOUNTING ASSEMBLY FIXED WITH RESPECT TO SAID FILAMENT ELEMENTS, MEANS FOR SUSPENDING ONE END OF SAID FILAMENT ELEMENTS FROM SAID MOUNTING ASSEMBLY, SAID MEANS FOR SUSPENDING BEING FREELY PIVOTED ABOUT A SINGLE POINT OF SAID MOUNTING ASSEMBLY AND MEANS FOR RIGIDLY SECURING THE OTHER END OF SAID FILAMENT ELEMENTS SO THAT SAID FILAMENT ELEMENTS ARE MAINTAINED UNDER SUBSTANTIALLY EQUAL TENSION. 